Sulphur oxides (SO_x) represent a major air pollutant and are controlled by national and international regulations. CuO/SiO₂ materials are known as SO_x trap materials. However, their large-scale development is still hampered by the sintering of the active phase over multiple adsorption/regeneration cycles, leading to the progressive decrease in SO_x adsorption capacities of the adsorbent. In this work, SBA-15 organised mesoporous silica was functionalized with highly dispersed Cu²⁺-based species. The as-obtained adsorbent was then assessed as a regenerable SO_x trap material. An extended characterisation was performed along with adsorption/regeneration cycles to correlate the evolution of the copper species with the performance of the adsorbent under different regenerative treatments. Thermal regeneration at 600 °C under pure N₂ leads to the formation of Cu⁺-based species, enabling a significant increase in SO_x chemisorption efficiency, which nevertheless decreases during the subsequent cycles due to progressive sintering of the active phase, leading to bulky copper(II) oxide particles. Regeneration under reductive conditions (0.5 vol% of H₂ in N₂) was then investigated as a way to decrease the regeneration temperature and limit this sintering process. It was found that the general behaviour of the copper-based species was very sensitive to the regeneration temperature. At 600 °C, the active phase was completely converted into large metallic copper particles, giving rise to a fast decrease in SO_x adsorption capacity of the adsorbent due to partial obstruction of the SBA-15 silica porosity. Conversely, when this regeneration was performed at 280 °C, no decrease in performances was noticed, and the copper species remained as a highly dispersed phase on the silica support.

中文翻译：

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CuO / SBA-15型SO _x吸附剂的结构性能关系：不同再生处理下铜基物种的演化

硫氧化物（SO _x）代表主要的空气污染物，受到国家和国际法规的控制。CuO / SiO ₂材料被称为SO _x捕集材料。然而，在多个吸附/再生循环中，活性相的烧结仍然阻碍了它们的大规模开发，导致吸附剂的SO _x吸附能力逐渐降低。在这项工作中，SBA-15组织的介孔二氧化硅被高度分散的基于Cu ²⁺的物质官能化。然后将获得的吸附剂评估为可再生的SO _x捕获材料。进行了扩展的表征以及吸附/再生循环，以将铜种类的演变与不同再生处理下吸附剂的性能相关联。在纯N ₂下于600°C的温度下进行热再生会导致形成基于Cu ⁺的物质，从​​而使SO _x的化学吸附效率显着提高，但由于活性相的逐步烧结，其在随后的循环中仍会降低，从而导致体积增大氧化铜（II）颗粒。在还原条件下的再生（h的0.5体积％的₂的N ₂然后研究）作为降低再生温度并限制该烧结过程的一种方法。发现铜基物质的一般行为对再生温度非常敏感。在600℃下，将活性相完全转变成较大的金属铜粒子，从而产生了在SO快速降低_X的吸附剂的吸附能力由于SBA-15二氧化硅孔隙率的部分阻塞。相反，当在280℃下进行该再生时，没有观察到性能降低，并且铜物质以高度分散相的形式保留在二氧化硅载体上。